Okay, I have to put these two disclaimers:IF YOU HAVEN'T SEEN THE EPISODES OF THE SECOND SEASON AND DO NOT WANT SPOILERS, DO NOT PROCEED!!!! If you are remaining in the dark for what happens until you can see the episodes in their entirety when the DVD comes to the US, then A. I salute you. You have more restraint than me. And B. Do NOT read the following, because I spoil things.
Secondly, I have not actually seen the episodes of the second season yet. (Which, by the way, can someone answer this for me? In the first episode of season two, does the tension and situation in the pool actually get sidetracked because Moriarty gets a phone call??? And what's his real ringtone?) Anyway, these are thoughts based on what I've been able to glean out because of YouTube. But, especially people in England who have seen the episodes, I'd love to know what you think. And please tag others for this note, as there is a limit for how many people I can tag.
If I get any details wrong, it's because I've misinterpreted them from the YouTube videos. It's hard to actually find longer clips of the actual show. Most people have these montage things to whatever song they feel fits the Holmes and Watson 'bromance,' or is some kind of tribute to Holmes's life.
On to the theories.
First, Moriarty's suicide. From what I can tell, Moriarty spends this episode ruining Sherlock's reputation, calling him a fake, insisting his deductive skills are no more than magic tricks, basically. I don't know who, if anyone, begins to question Sherlock, but I saw some clip where he's actually arrested by Lestrade. Then, when Sherlock and Moriarty are on the rooftop, it's revealed there are assassins waiting for a signal to take out Watson, Mrs. Hudson, and Lestrade.
Moriarty says, if I'm not mistaken, some kind of line that amounts to the assassins never being called off unless he does it? Okay, just looked at the YouTube footage again. He says as long as he's alive, Sherlock's friends have a chance to live, and that "your friends will die if you don't."
Now, watching how Sherlock reacts after Moriarty supposed kills himself gives some clues right there. He acts completely distraught (well, 'completely' for Sherlock, anyway,) and shocked. A. I don't think Moriarty's actually dead. I do agree with the ones saying that if he'd shot himself in the mouth, his head would be blown off. He wouldn't just have a trail of blood running from the back of his head. But think about the camera angle when the gun goes off, and how Sherlock's left arm swung out just before/as the shot's going off. I think he hit the gun out of the way so that yes, Moriarty was shot, hence the blood, but it wasn't enough to kill him. Unfortunately, it was a good enough job to fool Sherlock, who had the completely distraught moment, because he saw this as a possibility. He knew what he'd have to do--fake his own death.
Which brings me to Molly. Everyone is hypothesizing, because of her perception of him, that she was in on him faking his death, and helped him do it. I think that's wrong. I think the "you remind me of my dad" soliloquy showed Sherlock that she would be too perceptive to believe that he'd actually killed himself. I think he saw that she would begin her own investigation into his supposed 'death,' and get herself into worse trouble, because Moriarty's men have still gotta be out there. I have no idea what he could have asked her help with, but I think it was something other than his faked death. I think it was something to make it seem like he was fully letting her in, so that when the time came to fake his death, she'd be fully taken in and believe that Sherlock Holmes was no more, just like everyone else.
Which brings me to Sherlock himself. I freakin' LOVE Benedict Cumberbatch. His acting up on the rooftop was amazing. Anyway, my analysis. A lot of people have said that the crying was out of character for Sherlock. To a degree, they're right, and when I saw the first few thirty second clips and tried to piece them together, I agreed. Now, I've changed my mind. I think it was very IN-character for him. Think about the Blind Banker episode, when he faked such emotion when the husband died and he was talking to the wife. And then the bubbly-ness in his voice when he buzzed the lady in the upstairs apartment who had just moved in. He does whatever the situation calls for. Except this situation was the last resort that he hadn't wanted to get to, and as he says in the Hounds of Baskerville, "I don't have friends. I just have one." He knows how much this is going to hurt John, but he'd rather have him emotionally hurt than shot by a sniper. And I think, though he knew John wouldn't believe it, that he had to try and tell him that he was indeed a fake. Or perhaps he just needed to have evidence one last time of John's unwavering confidence in him in order to go through with what he had planned.
Okay, these are my theories. Let me know what you think. :)